UV LED Absorbance Measurement with Reference Detector
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Solution Overview
Problem
Current analytical instruments for detecting proteins and nucleic acids in the deep UV region face issues with light source stability, environmental concerns, heat generation, and unsuitability for miniaturization due to the use of mercury, deuterium, and xenon lamps, as well as limitations in sensitivity, linearity, and dynamic range when using light-emitting diodes without band pass filters or reference detectors.
Innovation Solution
A method and apparatus utilizing UV light-emitting diodes with a band pass filter and a reference detector, which provides a narrow bandwidth and compensates for intensity changes, allowing for accurate measurement of light absorbance and concentration determination of substances by adjusting the wavelength and path length, and using a carousel or MEMS mirror for precise light delivery.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If mercury, deuterium, or xenon lamps are used as light sources, then UV light detection capability is achieved, but device size increases and miniaturization becomes difficult
Solution Approach 1:
The patent replaces traditional mechanical lamp-based light sources (mercury, deuterium, xenon lamps) with light-emitting diodes (LEDs) that utilize electroluminescence in semiconductor materials. This substitution enables UV light generation in a compact form factor, allowing miniaturization of the analytical instrument while maintaining the necessary UV detection capability for proteins and nucleic acids.
Solution Approach 2:
The patent employs LEDs with adjustable emission wavelengths by selecting different semiconductor materials and bandgap parameters. This allows the light source to be tuned to specific UV wavelengths (e.g., 280 nm for proteins, 260 nm for nucleic acids) without requiring large lamp assemblies, thereby achieving both compact size and wavelength-specific detection capability.
2Illumination intensity
If mercury, deuterium, or xenon lamps are used as light sources, then UV light is generated, but heat generation increases
Solution Approach 1:
The patent replaces high-voltage lamp-based systems that generate significant heat through incandescence and arc discharge with low-power LED systems that convert electrical energy directly to light through electroluminescence. This substitution dramatically reduces heat generation while maintaining UV light output, eliminating the need for complex cooling systems and improving overall system efficiency.
Solution Approach 2:
The patent employs pulse-width modulation (PWM) control of the LED current to deliver UV light in controlled pulses rather than continuous operation. This periodic activation reduces average power consumption and heat generation while maintaining sufficient UV intensity for detection, allowing the system to operate without active cooling mechanisms.
3Illumination intensity
If mercury, deuterium, or xenon lamps are used as light sources, then UV light is produced, but environmental harm increases
Solution Approach 1:
The patent replaces mercury-containing lamps that require special disposal procedures with LED components that have no hazardous materials. The LEDs have sufficient operational lifetimes for analytical applications and can be disposed of through standard electronic waste channels, eliminating the environmental burden of mercury disposal while maintaining UV light generation capability.
Solution Approach 2:
The patent substitutes lamp-based UV sources that emit broad-spectrum UV radiation (including harmful wavelengths) with LED-based sources that can be engineered to emit only at specific, beneficial wavelengths. This substitution reduces environmental harm by eliminating unnecessary UV radiation and the associated risks of lamp breakage and mercury contamination.
4Device complexity
If LEDs are used without band pass filters or reference detectors, then device complexity is reduced, but measurement precision deteriorates
Solution Approach 1:
The patent introduces band pass filters as optical intermediaries that selectively transmit only the desired UV wavelength range while blocking other wavelengths. This allows the use of simple LEDs as light sources while maintaining measurement precision, as the filters ensure that only the relevant UV light reaches the sample and detector, eliminating interference from other spectral regions.
Solution Approach 2:
The patent incorporates reference detectors that monitor the LED output intensity and provide feedback signals for real-time correction of measurements. This feedback mechanism compensates for LED intensity drift and fluctuations, maintaining high measurement precision and linearity without requiring complex light source stabilization systems.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution enhances sensitivity, linearity, and dynamic range, providing a reliable, adaptable, and cost-effective means to measure protein and nucleic acid concentrations with improved stability and miniaturization potential, while reducing environmental impact.
Implementation Method 1
utilizing UV light-emitting diodes
Implementation Method 2
Light emitting diodes (LEDs), which emit in the visible region of the spectrum
Implementation Method 3
with a band pass filter and a reference detector, which provides a narrow bandwidth
Implementation Method 4
measuring the absorbance of light of a substance in a solution using visible or non visible light, the substance having a capacity to absorb light at a specific wavelength or wavelengths
Implementation Method 5
The concentration of the substance can be determined by use of the Beer Lambert Law
Implementation Method 6
a reference detector, which provides a narrow bandwidth and compensates for intensity changes
Data Source
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AI summary
Disclosed is an apparatus for measuring the absorbance of a substance in a solution, comprising: i) a sample cell (30) of known path length (b) for containing said solution (S), said cell being transparent to light of a predefined wavelength spectrum; ii) plural LED's each being independently operable by means of a controller (25) each for emitting light, within said predefined wavelength spectrum, along a light path; iii) a band pass filter (22) in the light path; iv) a beam splitter (24) for dividing light from said source propagating along the path into a first portion and a second portion, said first portion being directable by the beam splitter toward a reference detector (42) and said second portion being directable into the cell (30); v) a reference detector (42) for detecting the intensity of said first portion of light directed by said beam splitter; and vi) a sample detector (40) for detecting the intensity of the second portion propagating from the cell; the apparatus allowing a sample in the cell to be inexpensively subjected to more than one wavelength of light for quicker or more accurate analysis.